1. Technical Field of the Invention
The present invention relates to a method and system for tracking items over a wide area, and in particular, for tracking items during transport within a cellular packet data network.
2. Description of Related Art
Wide area item tracking systems are currently used for partial location tracking of pallets, loads, containers, trucks, and the like. Such systems are useful, for instance, in the parcel shipping industry and for supply delivery in just-in-time manufacturing operations (i.e., where supplies reach the manufacturing plant at approximately the time they are needed). In existing systems, the identity of each particular item is entered into the tracking system at each control stage (e.g., when the item is loaded onto a truck) or when the item reaches a manufacturing plant. Typically, manual entry of the item's identity is performed using a bar code reader to scan in an item identifier or using a keypad to key in an item identifier. Between each control stage, however, there is no way to determine the current location of the item. Instead, these systems can generally only tell the customer what is the last control point that his or her item has reached. As a result, the customer cannot tell if the delivery is progressing or if, for example, the item is simply sitting in a truck at a loading dock. Such systems are too inaccurate and are insufficient for locating important items in a parcel delivery service or in a just-in-time manufacturing supply operation.
As one alternative, handling zone item tracking systems are also available for use in the manufacturing industry. Such systems, however, offer only limited indoor coverage and cannot provide tracking for wide area delivery applications. Another alternative is to use a Global Positioning Satellite (GPS) system for tracking trucks and other mobile shipping containers. The position of the truck or container, as determined by the GPS system, can then be transmitted to a monitoring center. GPS systems, however, are too expensive for most applications.
There is a need, therefore, for a system and method for providing more accurate and efficient item tracking across a wide area at a relatively low cost. Such a system would provide information about the current geographical location of a particular item and would be useful, for example, for customers, suppliers, and delivery service providers in the parcel delivery and just-in-time manufacturing industries.